花 2 小时就能做出一个 RSS 生成器

Wait no longer! Create RSS feeds for all websites you care about and read them from the comfort of your feed reader.
现在越来越多的网站都不支持 RSS 订阅了,而作为 RSS 的忠实粉丝,还是希望有个工具可以将自己关注的网站内容聚合在一起,然后实时推送到手机上,及时获取最新消息和新闻动态。
所以今天就让我们用 2 个小时,撸一个 RSS 生成器。
本文的主角仍然是 Laravel。

1. 搭建 Laravel 骨架

由于需要有一个后台,添加我们关注的网站,所以我们还是沿用 laravel-damin 插件。
// 1. 创建 Laravel 5.5版本项目
composer create-project –prefer-dist laravel/laravel:5.5 lrss
cd lrss
cp .env.example .env
php artisan key:generate
// 2. 使用 laravel-admin 插件
composer require encore/laravel-admin “1.5.*”
php artisan vendor:publish –provider=”Encore\Admin\AdminServiceProvider”
php artisan admin:install
注:如出现问题:SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 767 bytes
解决方案:在 AppServiceProvider.php 加入默认字符串长度
use Illuminate\Support\Facades\Schema;
public function boot()
{
Schema::defaultStringLength(191);
}
刚巧,我们想借助 Symfonys 提供的 DomCrawler 插件,来解析网站的 xpath 信息,发现 laravel-admin插件有引入:

2. 解析 XPath

之前有想借助 huginn 这个神器来生成我们的 RSS Feed,主要参看文章:让所有网页变成RSS —— Huginn http://git.huginn.cn/docs/%E8%AE%A9%E6%89%80%E6%9C%89%E7%BD%91%E9%A1%B5%E5%8F%98%E6%88%90RSS%E2%80%94%E2%80%94Huginn.html
但在实际使用中,发现一直出现 Huginn 无故宕机,或者后台 jobs 动不动就失败。这才有了自己撸个工具的想法。
但 Huginn 给了我灵感,可以利用解析 XPath 来生成 RSS Feed。

创建 Xpath 控制器

为了验证输入的 XPath 信息的准确性,我们可以参考 Huginn,
首先在 Huginn 测试 XPath 的效果,在创建 WebsiteAgent 界面,输入如下信息:
{
“expected_update_period_in_days”: “2”,
“url”: “http://www.woshipm.com/”,
“type”: “html”,
“mode”: “on_change”,
“extract”: {
“title”: {
“xpath”: “//div[@class=\”postlist-item u-clearfix\”]/div[2]/h2/a/text()”,
“value”: “normalize-space(.)”
},
“desc”: {
“xpath”:
“//div[@class=\”postlist-item u-clearfix\”]/div[2]/p/text()”,
“value”: “normalize-space(.)”
},
“url”: {
“xpath”: “//div[@class=\”postlist-item u-clearfix\”]/div[2]/h2/a”,
“value”: “@href”
}
}
}
然后点 「Dry Run」即可测试:
最后根据 Huginn 填入的信息,我们来创建 Xpath Controller
// bash
php artisan make:model Xpath -m
// migration
public function up()
{
Schema::create(‘xpaths’, function (Blueprint $table) {
$table->increments(‘id’);
// url
$table->string(‘url’, 250);
$table->string(“urldesc”, 250);
// title
$table->string(‘titlexpath’, 250);
$table->string(‘titlevalue’, 100)
->nullable();
// desc
$table->string(‘descxpath’, 250);
$table->string(‘descvalue’, 100)
->nullable();
// url
$table->string(“preurl”, 50)->nullable();
$table->string(‘urlxpath’, 250);
$table->string(‘urlvalue’, 100)
->nullable();
$table->timestamps();
});
}
// migrate
php artisan migrate
// 创建 admin/Controller
php artisan admin:make XpathController –model=App\\Xpath
// 建立 route
$router->resource(‘xpaths’, XpathController::class);
// 加入到 admin 的 menu 中
// 略
注: 可以参考之前的文章:推荐一个 Laravel admin 后台管理插件

CURD XPath

有了 laravel-admin 插件,操作 XPath 信息就好简单了,直接看代码:
<?php
namespace App\Admin\Controllers;
use App\Xpath;
use Encore\Admin\Form;
use Encore\Admin\Grid;
use Encore\Admin\Facades\Admin;
use Encore\Admin\Layout\Content;
use App\Http\Controllers\Controller;
use Encore\Admin\Controllers\ModelForm;
class XpathController extends Controller
{
use ModelForm;
/**
* Index interface.
*
* @return Content
*/
public function index()
{
return Admin::content(function (Content $content) {
$content->header(‘header’);
$content->description(‘description’);
$content->body($this->grid());
});
}
/**
* Edit interface.
*
* @param $id
* @return Content
*/
public function edit($id)
{
return Admin::content(function (Content $content) use ($id) {
$content->header(‘header’);
$content->description(‘description’);
$content->body($this->form()->edit($id));
});
}
/**
* Create interface.
*
* @return Content
*/
public function create()
{
return Admin::content(function (Content $content) {
$content->header(‘header’);
$content->description(‘description’);
$content->body($this->form());
});
}
/**
* Make a grid builder.
*
* @return Grid
*/
protected function grid()
{
return Admin::grid(Xpath::class, function (Grid $grid) {
$grid->id(‘ID’)->sortable();
$grid->column(‘url’);
$grid->column(‘urldesc’, “描述”);
$grid->column(‘titlexpath’);
$grid->column(‘titlevalue’);
$grid->column(‘descxpath’);
$grid->column(‘descvalue’);
$grid->column(‘preurl’);
$grid->column(‘urlxpath’);
$grid->column(‘urlvalue’);
$grid->created_at();
$grid->updated_at();
});
}
/**
* Make a form builder.
*
* @return Form
*/
protected function form()
{
return Admin::form(Xpath::class, function (Form $form) {
$form->display(‘id’, ‘ID’);
// url
$form->text(‘url’, ‘链接’)
->placeholder(‘请输入解析的网址’)
->rules(‘required|min:5|max:250’);
$form->text(‘urldesc’, ‘一句话描述’)
->placeholder(‘一句话描述’)
->rules(‘required|min:5|max:250’);
// title
$form->divide();
$form->text(‘titlexpath’, ‘title xpath’)
->placeholder(‘请输入标题 xpath’)
->rules(‘required|min:5|max:250’);
$form->text(‘titlevalue’, ‘title value 默认可以不填’)
->default(”)
->rules(‘max:100’);
// desc
$form->divide();
$form->text(‘descxpath’, ‘desc xpath’)
->placeholder(‘请输入详情 xpath’)
->rules(‘required|min:5|max:250’);
$form->text(‘descvalue’, ‘desc value,默认可以不填’)
->default(”)
->rules(‘max:100’);
// url
$form->divide();
$form->text(‘preurl’, ‘url 前缀’)
->placeholder(‘请输入文章的url 前缀’)
->rules(‘max:50’);
$form->text(‘urlxpath’, ‘url xpath’)
->placeholder(‘请输入文章的url xpath’)
->rules(‘required|min:5|max:250’);
$form->text(‘urlvalue’, ‘url value 默认可以不填’)
->default(”)
->rules(‘max:100’);
$form->divide();
$form->display(‘created_at’, ‘Created At’);
$form->display(‘updated_at’, ‘Updated At’);
});
}
}
添加两个网站信息试试:

XPath 转为 RSS Feed

1. 根据填入的 Xpath 信息,解析内容:
public static function analysis(XpathModel $model) {
$html = file_get_contents($model->url);
$crawler = new Crawler($html);
$titlenodes = $crawler->filterXPath($model->titlexpath);
$titles = self::getValueByNodes($titlenodes, $model->titlevalue);
$descnodes = $crawler->filterXPath($model->descxpath);
$desces = self::getValueByNodes($descnodes, $model->descvalue);
$urlnodes = $crawler->filterXPath($model->urlxpath);
$urls = self::getValueByNodes($urlnodes, $model->urlvalue);
return RssFeeds::feeds($model, $titles, $desces, $urls);
}
// 通过规则获取 nodes 的值
public static function getValueByNodes(Crawler $crawler, $key = null) {
return $crawler->each(function (Crawler $node) use ($key) {
if (empty($key)) {
return trim($node->text());
} else {
return $node->attr($key);
}
});
}
2. 将获得 title、desc 和 url 数组装入 Feed Item 中,构建 RSS。
public static function feeds(Xpath $xpath, $titles = [], $desces = [], $urls = []) {
if (!empty($xpath->preurl)) {
$preurl = $xpath->preurl;
$urlss = collect($urls)->map(function ($url, $key) use ($preurl) {
return $preurl.trim($url);
});
} else {
$urlss = collect($urls);
}
return response()
->view(‘rss’,
[
‘xpath’ => $xpath,
‘titles’ => $titles,
‘desces’ => $desces,
‘urls’ => $urlss->toArray(),
‘pubDate’ => Carbon::now()
])
->header(‘Content-Type’, ‘text/xml’);
}
3. 编写 blade 模板
<rss version=”2.0″ xmlns:atom=”http://www.w3.org/2005/Atom”>
<channel>
<title>{{ $xpath->url or ‘ title’ }}</title>
<description>{{ $xpath->urldesc or ‘描述’ }}</description>
<link>{{ $xpath->url }}</link>
<atom:link href=”{{ url(“/feed/$xpath->id”) }}” rel=”self” type=”application/rss+xml”/>
<pubDate>{{ $pubDate }}</pubDate>
<lastBuildDate>{{ $pubDate }}</lastBuildDate>
<generator>coding01</generator>
@foreach ($titles as $key => $title)
<item>
<title>{{ $title }}</title>
<link>{{ $urls[$key] }}</link>
<description>{{ $desces[$key] }}</description>
<pubDate>{{ $pubDate }}</pubDate>
<author>coding01</author>
<guid>{{ $urls[$key] }}</guid>
<category>{{ $title }}</category>
</item>
@endforeach
</channel>
</rss>
4. 最终来看看效果吧,为每一个网站做成一个 RSS:

RSS 实时订阅

至此,当前的 Laravel 代码告一段落了,但为了达到及时推送内容到手机的目标,我借助了两个工具:
  1. Tiny Tiny RSS
  2. IFTTT + 钉钉
把制作好的 RSS 链接加入 Tiny Tiny RSS 上,每隔半个小时,更新一次,获取最新的内容:
然后借助 IFTTT 绑定钉钉的群机器人 Webhook:
最后在手机钉钉或者在 PC 上就能及时收到最新资讯和信息了:

总结

今天花了 2 个小时,主要是借助 laravel-amin 和 symfony/dom-crawler 插件来自己动手搭建一个 RSS Feed 生成工具Demo。
接下来还有待于继续优化,如向 https://feed43.com/ 那样,输入 Web URL 就能生成 RSS Feed,又能根据实际需要自己设定更新时间等。
最后,代码以放在 github 上,可供参考: https://github.com/fanly/lrss

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